01 - Bring a large pot of generously salted water to a rolling boil. Add the tortellini and cook according to package directions until al dente. Drain well and set aside.
02 - While the tortellini cooks, toss the diced chicken breasts with salt, pepper, and Italian seasoning until evenly coated. Heat olive oil in a large skillet over medium-high heat. Sear the chicken until deeply golden and cooked through, approximately 5 to 7 minutes. Transfer to a plate and tent loosely with foil.
03 - In the same skillet, melt the butter over medium heat. Add the chopped onion and sauté for 2 to 3 minutes until softened and translucent. Stir in the minced garlic and cook for 1 minute until fragrant, taking care not to let it brown.
04 - Pour the chicken broth into the skillet to deglaze, using a wooden spoon to scrape up all the caramelized bits from the bottom. Reduce heat to medium.
05 - Stir in the heavy cream and Parmesan cheese. Continue stirring until the cheese has fully melted and the sauce thickens slightly, about 3 minutes.
06 - Add the fresh spinach to the skillet and gently fold it into the sauce until wilted, approximately 1 to 2 minutes.
07 - Return the seared chicken to the skillet along with the drained tortellini. Gently toss everything together until evenly coated in the creamy sauce. Taste and adjust seasoning with additional salt and pepper as needed. Serve immediately, garnished with extra Parmesan and chopped fresh parsley.